This invention relates to support appliances, such as beds, having articulated sections and in particular provides a pneumatic system for causing articulation of the sections.
In U.S. Pat. No. 3,909,858 to Frank E. M. Ducker (the disclosure of which is incorporated herein by reference) a support appliance, such as a bed, is described in which the patient support surface consists of a number of air sacs or cells which are inflated to various pressures depending upon the weight to be supported at different points along the bed. By adjusting the pressures in different cells or groups of cells in this way, the incidence of bed sores can be reduced and the healing process in the case of patients having burns or other lesions can be accelerated. The appliance described in the above U.S. Patent also provides for the circulation of thermostatically controlled air through the cells so that the maintenance of optimum temperature of the patient can be facilitated. In addition, the above mentioned U.S. Patent contemplates an articulated construction in which the head and foot section are pivotable with respect to a center section. This is an important feature which greatly reduces the physical labour necessary in the nursing of seriously ill patients. Various mechanical, hydraulic and electromechanical systems have been investigated for raising and lowering sections of hospital beds and similar support appliances but such systems mostly suffer from the disadvantages of excessive complexity and expense, particularly where more than one pivoting action is required.